“…In recent years, DIF has been widely used to ensure the internal validity of psychological, educational, and medical quality of life test scores across different demographic variables such as gender (e.g., Zampetakis et al, 2017), ethnic background (e.g., Jones et al, 2016), age groups (e.g., Estabrook et al, 2015), and socioeconomic status (e.g., Thielemann et al, 2018). DIF assesses whether the probability of responding to a specific item is different for different groups after controlling the ability [10,11]. There are two forms of DIF known as uniform and nonuniform.…”